llvm::ARMAsmBackend Class Reference

#include "Target/ARM/MCTargetDesc/ARMAsmBackend.h"

Inheritance diagram for llvm::ARMAsmBackend:

Public Member Functions
	ARMAsmBackend (const Target &T, bool isThumb, llvm::endianness Endian)
unsigned	getNumFixupKinds () const override
	Get the number of target specific fixup kinds.
bool	hasNOP (const MCSubtargetInfo *STI) const
std::optional< MCFixupKind >	getFixupKind (StringRef Name) const override
	Map a relocation name used in .reloc to a fixup kind.
const MCFixupKindInfo &	getFixupKindInfo (MCFixupKind Kind) const override
	Get information on a fixup kind.
bool	shouldForceRelocation (const MCAssembler &Asm, const MCFixup &Fixup, const MCValue &Target, const MCSubtargetInfo *STI) override
	Hook to check if a relocation is needed for some target specific reason.
unsigned	adjustFixupValue (const MCAssembler &Asm, const MCFixup &Fixup, const MCValue &Target, uint64_t Value, bool IsResolved, MCContext &Ctx, const MCSubtargetInfo *STI) const
void	applyFixup (const MCAssembler &Asm, const MCFixup &Fixup, const MCValue &Target, MutableArrayRef< char > Data, uint64_t Value, bool IsResolved, const MCSubtargetInfo *STI) const override
	Apply the Value for given Fixup into the provided data fragment, at the offset specified by the fixup and following the fixup kind as appropriate.
unsigned	getRelaxedOpcode (unsigned Op, const MCSubtargetInfo &STI) const
bool	mayNeedRelaxation (const MCInst &Inst, const MCSubtargetInfo &STI) const override
	Check whether the given instruction may need relaxation.
const char *	reasonForFixupRelaxation (const MCFixup &Fixup, uint64_t Value) const
bool	fixupNeedsRelaxation (const MCFixup &Fixup, uint64_t Value) const override
	Simple predicate for targets where !Resolved implies requiring relaxation.
void	relaxInstruction (MCInst &Inst, const MCSubtargetInfo &STI) const override
	Relax the instruction in the given fragment to the next wider instruction.
bool	writeNopData (raw_ostream &OS, uint64_t Count, const MCSubtargetInfo *STI) const override
	Write an (optimal) nop sequence of Count bytes to the given output.
void	handleAssemblerFlag (MCAssemblerFlag Flag) override
	Handle any target-specific assembler flags. By default, do nothing.
unsigned	getPointerSize () const
bool	isThumb () const
void	setIsThumb (bool it)
Public Member Functions inherited from llvm::MCAsmBackend
	MCAsmBackend (const MCAsmBackend &)=delete
MCAsmBackend &	operator= (const MCAsmBackend &)=delete
virtual	~MCAsmBackend ()
bool	allowLinkerRelaxation () const
virtual bool	allowAutoPadding () const
	Return true if this target might automatically pad instructions and thus need to emit padding enable/disable directives around sensative code.
virtual bool	allowEnhancedRelaxation () const
	Return true if this target allows an unrelaxable instruction to be emitted into RelaxableFragment and then we can increase its size in a tricky way for optimization.
virtual void	reset ()
	lifetime management
std::unique_ptr< MCObjectWriter >	createObjectWriter (raw_pwrite_stream &OS) const
	Create a new MCObjectWriter instance for use by the assembler backend to emit the final object file.
std::unique_ptr< MCObjectWriter >	createDwoObjectWriter (raw_pwrite_stream &OS, raw_pwrite_stream &DwoOS) const
	Create an MCObjectWriter that writes two object files: a .o file which is linked into the final program and a .dwo file which is used by debuggers.
virtual std::unique_ptr< MCObjectTargetWriter >	createObjectTargetWriter () const =0
virtual unsigned	getMinimumNopSize () const
	Returns the minimum size of a nop in bytes on this target.
virtual unsigned	getMaximumNopSize (const MCSubtargetInfo &STI) const
	Returns the maximum size of a nop in bytes on this target.
virtual bool	writeNopData (raw_ostream &OS, uint64_t Count, const MCSubtargetInfo *STI) const =0
	Write an (optimal) nop sequence of Count bytes to the given output.
virtual void	finishLayout (MCAssembler const &Asm) const
	Give backend an opportunity to finish layout after relaxation.
virtual void	handleAssemblerFlag (MCAssemblerFlag Flag)
	Handle any target-specific assembler flags. By default, do nothing.
virtual uint64_t	generateCompactUnwindEncoding (const MCDwarfFrameInfo *FI, const MCContext *Ctxt) const
	Generate the compact unwind encoding for the CFI instructions.
virtual bool	isMicroMips (const MCSymbol *Sym) const
	Check whether a given symbol has been flagged with MICROMIPS flag.
bool	isDarwinCanonicalPersonality (const MCSymbol *Sym) const
virtual bool	shouldInsertExtraNopBytesForCodeAlign (const MCAlignFragment &AF, unsigned &Size)
	Hook to check if extra nop bytes must be inserted for alignment directive.
virtual bool	shouldInsertFixupForCodeAlign (MCAssembler &Asm, MCAlignFragment &AF)
	Hook which indicates if the target requires a fixup to be generated when handling an align directive in an executable section.
virtual bool	evaluateTargetFixup (const MCAssembler &Asm, const MCFixup &Fixup, const MCFragment *DF, const MCValue &Target, const MCSubtargetInfo *STI, uint64_t &Value, bool &WasForced)
virtual bool	handleAddSubRelocations (const MCAssembler &Asm, const MCFragment &F, const MCFixup &Fixup, const MCValue &Target, uint64_t &FixedValue) const
virtual bool	fixupNeedsRelaxationAdvanced (const MCAssembler &Asm, const MCFixup &Fixup, bool Resolved, uint64_t Value, const MCRelaxableFragment *DF, const bool WasForced) const
	Target specific predicate for whether a given fixup requires the associated instruction to be relaxed.
virtual bool	relaxDwarfLineAddr (const MCAssembler &Asm, MCDwarfLineAddrFragment &DF, bool &WasRelaxed) const
virtual bool	relaxDwarfCFA (const MCAssembler &Asm, MCDwarfCallFrameFragment &DF, bool &WasRelaxed) const
virtual std::pair< bool, bool >	relaxLEB128 (const MCAssembler &Asm, MCLEBFragment &LF, int64_t &Value) const

Additional Inherited Members
Public Attributes inherited from llvm::MCAsmBackend
const llvm::endianness	Endian
const unsigned	RelaxFixupKind
	Fixup kind used for linker relaxation.
Protected Member Functions inherited from llvm::MCAsmBackend
	MCAsmBackend (llvm::endianness Endian, unsigned RelaxFixupKind=MaxFixupKind)

Detailed Description

Definition at line 20 of file ARMAsmBackend.h.

Constructor & Destructor Documentation

ARMAsmBackend()

llvm::ARMAsmBackend::ARMAsmBackend ( const Target &  T, bool  isThumb, llvm::endianness  Endian  )

inline

Definition at line 23 of file ARMAsmBackend.h.

Member Function Documentation

adjustFixupValue()

unsigned ARMAsmBackend::adjustFixupValue	(	const MCAssembler &	Asm,
		const MCFixup &	Fixup,
		const MCValue &	Target,
		uint64_t	Value,
		bool	IsResolved,
		MCContext &	Ctx,
		const MCSubtargetInfo *	STI
	)		const

Definition at line 440 of file ARMAsmBackend.cpp.

References A, assert(), llvm::MCAsmBackend::Endian, Fixup, llvm::ARM::fixup_arm_adr_pcrel_12, llvm::ARM::fixup_arm_blx, llvm::ARM::fixup_arm_condbl, llvm::ARM::fixup_arm_condbranch, llvm::ARM::fixup_arm_ldst_abs_12, llvm::ARM::fixup_arm_ldst_pcrel_12, llvm::ARM::fixup_arm_mod_imm, llvm::ARM::fixup_arm_movt_hi16, llvm::ARM::fixup_arm_movw_lo16, llvm::ARM::fixup_arm_pcrel_10, llvm::ARM::fixup_arm_pcrel_10_unscaled, llvm::ARM::fixup_arm_pcrel_9, llvm::ARM::fixup_arm_thumb_bcc, llvm::ARM::fixup_arm_thumb_bl, llvm::ARM::fixup_arm_thumb_blx, llvm::ARM::fixup_arm_thumb_br, llvm::ARM::fixup_arm_thumb_cb, llvm::ARM::fixup_arm_thumb_cp, llvm::ARM::fixup_arm_thumb_lower_0_7, llvm::ARM::fixup_arm_thumb_lower_8_15, llvm::ARM::fixup_arm_thumb_upper_0_7, llvm::ARM::fixup_arm_thumb_upper_8_15, llvm::ARM::fixup_arm_uncondbl, llvm::ARM::fixup_arm_uncondbranch, llvm::ARM::fixup_bf_branch, llvm::ARM::fixup_bf_target, llvm::ARM::fixup_bfc_target, llvm::ARM::fixup_bfcsel_else_target, llvm::ARM::fixup_bfl_target, llvm::ARM::fixup_le, llvm::ARM::fixup_t2_adr_pcrel_12, llvm::ARM::fixup_t2_condbranch, llvm::ARM::fixup_t2_ldst_pcrel_12, llvm::ARM::fixup_t2_movt_hi16, llvm::ARM::fixup_t2_movw_lo16, llvm::ARM::fixup_t2_pcrel_10, llvm::ARM::fixup_t2_pcrel_9, llvm::ARM::fixup_t2_so_imm, llvm::ARM::fixup_t2_uncondbranch, llvm::ARM::fixup_thumb_adr_pcrel_10, llvm::ARM::fixup_wls, llvm::FK_Data_1, llvm::FK_Data_2, llvm::FK_Data_4, llvm::FK_SecRel_2, llvm::FK_SecRel_4, llvm::ARM_AM::getSOImmVal(), llvm::ARM_AM::getT2SOImmVal(), llvm::MCSubtargetInfo::getTargetTriple(), llvm::MCSubtargetInfo::hasFeature(), I, llvm::Triple::isOSBinFormatCOFF(), llvm::Triple::isOSBinFormatELF(), joinHalfWords(), llvm::little, llvm::maxIntN(), llvm::minIntN(), reasonForFixupRelaxation(), llvm::MCContext::reportError(), swapHalfWords(), and llvm::MCSymbolRefExpr::VK_TLSCALL.

Referenced by applyFixup().

applyFixup()

void ARMAsmBackend::applyFixup ( const MCAssembler &  Asm, const MCFixup &  Fixup, const MCValue &  Target, MutableArrayRef< char >  Data, uint64_t  Value, bool  IsResolved, const MCSubtargetInfo *  STI  ) const

overridevirtual

Apply the Value for given Fixup into the provided data fragment, at the offset specified by the fixup and following the fixup kind as appropriate.

Errors (such as an out of range fixup value) should be reported via Ctx. The STI is present only for fragments of type MCRelaxableFragment and MCDataFragment with hasInstructions() == true.

Implements llvm::MCAsmBackend.

Definition at line 1128 of file ARMAsmBackend.cpp.

References adjustFixupValue(), assert(), llvm::big, llvm::Data, llvm::MCAsmBackend::Endian, llvm::FirstLiteralRelocationKind, Fixup, getFixupKindContainerSizeBytes(), getFixupKindNumBytes(), Idx, llvm::little, and llvm::Offset.

fixupNeedsRelaxation()

bool ARMAsmBackend::fixupNeedsRelaxation ( const MCFixup &  Fixup, uint64_t  Value  ) const

overridevirtual

Simple predicate for targets where !Resolved implies requiring relaxation.

Reimplemented from llvm::MCAsmBackend.

Definition at line 337 of file ARMAsmBackend.cpp.

References Fixup, and reasonForFixupRelaxation().

getFixupKind()

std::optional< MCFixupKind > ARMAsmBackend::getFixupKind ( StringRef  Name ) const

overridevirtual

Map a relocation name used in .reloc to a fixup kind.

Reimplemented from llvm::MCAsmBackend.

Reimplemented in llvm::ARMAsmBackendELF.

Definition at line 47 of file ARMAsmBackend.cpp.

getFixupKindInfo()

const MCFixupKindInfo & ARMAsmBackend::getFixupKindInfo ( MCFixupKind  Kind ) const

overridevirtual

Get information on a fixup kind.

Reimplemented from llvm::MCAsmBackend.

Definition at line 67 of file ARMAsmBackend.cpp.

References assert(), llvm::MCAsmBackend::Endian, llvm::FirstLiteralRelocationKind, llvm::FirstTargetFixupKind, llvm::FK_NONE, llvm::MCFixupKindInfo::FKF_IsAlignedDownTo32Bits, llvm::MCFixupKindInfo::FKF_IsPCRel, llvm::MCAsmBackend::getFixupKindInfo(), getNumFixupKinds(), llvm::little, and llvm::ARM::NumTargetFixupKinds.

getNumFixupKinds()

unsigned llvm::ARMAsmBackend::getNumFixupKinds ( ) const

inlineoverridevirtual

Get the number of target specific fixup kinds.

Implements llvm::MCAsmBackend.

Definition at line 26 of file ARMAsmBackend.h.

References llvm::ARM::NumTargetFixupKinds.

Referenced by getFixupKindInfo().

getPointerSize()

unsigned llvm::ARMAsmBackend::getPointerSize ( ) const

inline

Definition at line 71 of file ARMAsmBackend.h.

getRelaxedOpcode()

unsigned ARMAsmBackend::getRelaxedOpcode	(	unsigned	Op,
		const MCSubtargetInfo &	STI
	)		const

Definition at line 221 of file ARMAsmBackend.cpp.

References llvm::MCSubtargetInfo::hasFeature().

Referenced by mayNeedRelaxation(), and relaxInstruction().

handleAssemblerFlag()

void ARMAsmBackend::handleAssemblerFlag ( MCAssemblerFlag  Flag )

overridevirtual

Handle any target-specific assembler flags. By default, do nothing.

Reimplemented from llvm::MCAsmBackend.

Definition at line 208 of file ARMAsmBackend.cpp.

References llvm::MCAF_Code16, llvm::MCAF_Code32, and setIsThumb().

hasNOP()

bool llvm::ARMAsmBackend::hasNOP ( const MCSubtargetInfo *  STI ) const

inline

Definition at line 30 of file ARMAsmBackend.h.

References llvm::MCSubtargetInfo::hasFeature().

Referenced by writeNopData().

isThumb()

bool llvm::ARMAsmBackend::isThumb ( ) const

inline

Definition at line 72 of file ARMAsmBackend.h.

Referenced by writeNopData().

mayNeedRelaxation()

bool ARMAsmBackend::mayNeedRelaxation ( const MCInst &  Inst, const MCSubtargetInfo &  STI  ) const

overridevirtual

Check whether the given instruction may need relaxation.

Parameters

Inst	- The instruction to test.
STI	- The MCSubtargetInfo in effect when the instruction was encoded.

Reimplemented from llvm::MCAsmBackend.

Definition at line 244 of file ARMAsmBackend.cpp.

References llvm::MCInst::getOpcode(), and getRelaxedOpcode().

reasonForFixupRelaxation()

const char * ARMAsmBackend::reasonForFixupRelaxation	(	const MCFixup &	Fixup,
		uint64_t	Value
	)		const

Definition at line 258 of file ARMAsmBackend.cpp.

References checkPCRelOffset(), Fixup, llvm::ARM::fixup_arm_thumb_bcc, llvm::ARM::fixup_arm_thumb_br, llvm::ARM::fixup_arm_thumb_cb, llvm::ARM::fixup_arm_thumb_cp, llvm::ARM::fixup_bf_branch, llvm::ARM::fixup_bf_target, llvm::ARM::fixup_bfc_target, llvm::ARM::fixup_bfcsel_else_target, llvm::ARM::fixup_bfl_target, llvm::ARM::fixup_le, llvm::ARM::fixup_thumb_adr_pcrel_10, llvm::ARM::fixup_wls, llvm_unreachable, and llvm::Offset.

Referenced by adjustFixupValue(), and fixupNeedsRelaxation().

relaxInstruction()

void ARMAsmBackend::relaxInstruction ( MCInst &  Inst, const MCSubtargetInfo &  STI  ) const

overridevirtual

Relax the instruction in the given fragment to the next wider instruction.

Parameters

[out]	Inst	The instruction to relax, which is also the relaxed instruction.
	STI	the subtarget information for the associated instruction.

Reimplemented from llvm::MCAsmBackend.

Definition at line 342 of file ARMAsmBackend.cpp.

References llvm::MCInst::addOperand(), llvm::MCOperand::createImm(), llvm::MCOperand::createReg(), llvm::MCInst::dump_pretty(), llvm::MCInst::getOpcode(), getRelaxedOpcode(), OS, llvm::report_fatal_error(), and llvm::MCInst::setOpcode().

setIsThumb()

void llvm::ARMAsmBackend::setIsThumb ( bool  it )

inline

Definition at line 73 of file ARMAsmBackend.h.

Referenced by handleAssemblerFlag().

shouldForceRelocation()

bool ARMAsmBackend::shouldForceRelocation ( const MCAssembler &  Asm, const MCFixup &  Fixup, const MCValue &  Target, const MCSubtargetInfo *  STI  )

overridevirtual

Hook to check if a relocation is needed for some target specific reason.

Reimplemented from llvm::MCAsmBackend.

Definition at line 956 of file ARMAsmBackend.cpp.

References A, assert(), llvm::FirstLiteralRelocationKind, Fixup, llvm::ARM::fixup_arm_blx, llvm::ARM::fixup_arm_condbl, llvm::ARM::fixup_arm_thumb_bl, llvm::ARM::fixup_arm_thumb_blx, llvm::ARM::fixup_arm_thumb_br, llvm::ARM::fixup_arm_uncondbl, llvm::ARM::fixup_arm_uncondbranch, llvm::ARM::fixup_t2_condbranch, llvm::ARM::fixup_t2_uncondbranch, llvm::ELF::STT_FUNC, llvm::ELF::STT_GNU_IFUNC, and Sym.

writeNopData()

bool ARMAsmBackend::writeNopData ( raw_ostream &  OS, uint64_t  Count, const MCSubtargetInfo *  STI  ) const

overridevirtual

Write an (optimal) nop sequence of Count bytes to the given output.

If the target cannot generate such a sequence, it should return an error.

Returns

- True on success.

Implements llvm::MCAsmBackend.

Definition at line 373 of file ARMAsmBackend.cpp.

References llvm::MCAsmBackend::Endian, hasNOP(), isThumb(), OS, llvm::raw_ostream::write(), and llvm::support::endian::write().

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The documentation for this class was generated from the following files:

• lib/Target/ARM/MCTargetDesc/ARMAsmBackend.h
• lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp